Glucose is a simple sugar, a monosaccharide. Glucose belongs to the group of biomolecules known as carbohydrates. In general terms, glucose is the most important source of energy for the human body. Glucose is also known as D-glucose, dextrose and grape sugar. The name dextrose comes from the Latin dexter, which means right. Dextrose refers to the molecular arrangement of glucose, denoting its right-handed organization.
Origin of Glucose
The human body gets glucose through several different mechanisms. Your body gets glucose through intestinal absorption from food ingestion, especially carbohydrates. Additionally, your body gets glucose from the breakdown of glycogen, a process known as glycogenolysis. Glycogen is the molecule that stores glucose in your liver. Further, your body gets glucose from gluconeogenesis, the process of producing glucose from non-carbohydrate sources such as lactate, pyruvate, amino acids and glycerol. Only your liver and kidneys have the ability to release glucose.
Glucose and Brain Metabolism.
Glucose also supports your brain function. Glucose is an obligate metabolic fuel used by your brain when your body is under normal conditions. Your brain, however, cannot synthesize or store glucose. There are other organs in your body that can use fatty acids as a source of glucose. Levels of glucose in your plasma, the clear fluid part of blood, determine the levels of glucose in your brain.
Systemic Glucose Balance
Your hormones regulate the rate at which your body incorporates glucose into circulation or takes glucose out of circulation. Insulin is the hormone in charge of lowering plasma glucose. Glucagon and epinephrine are the biocompounds in charge of raising plasma glucose. In this way, your body continuously supplies glucose to the brain for immediate use and other organs for storage or immediate use.
Glucose as an Energy Source
Your insulin levels increase when your body experiences a rise in blood glucose levels. In effect, insulin stimulates your cells so that the glucose can enter the cells. Once inside your cells, glucose goes through a process that produces heat and adenosine triphosphate, ATP, a molecule that releases energy. This process occurs with or without oxygen. The process, however, functions more effectively with oxygen. When the process occurs without oxygen, complications such as muscle cramps can manifest in your body.
References
- "Williams Textbook of Endocrinology"; P. Reed Larsen, M.D., et al.; 2002
- "Integrative Medicine"; David Rakel; 2002
- Elmhurst College: Glucose
